public async Task ExistReview() { var options = new DbContextOptionsBuilder <ApplicationDbContext>() .UseInMemoryDatabase(databaseName: Guid.NewGuid().ToString()) .Options; var dbContext = new ApplicationDbContext(options); var repository = new EfDeletableEntityRepository <Review>(dbContext); var service = new ReviewService(repository); var reviews = this.GetReviews(); for (int i = 0; i < reviews.Count(); i++) { await repository.AddAsync(reviews[i]); } await repository.SaveChangesAsync(); var exist = service.ExistReview(1); Assert.True(exist); exist = service.ExistReview(10); Assert.False(exist); }